Advances in Caloric Cooling Technologiesiccr.xjtucompressor.com/file/ppt/5ICCR2017 Keynote--Hwang.pdfThe 8th International Conference on Compressors and Refrigeration, Xi’an, China,

The 8th International Conference on Compressors and Refrigeration, Xian, China, 2017

July 2017

Advances in Caloric Cooling Technologies

Yunho Hwang, Suxin Qian

Center for Environmental Energy EngineeringDepartment of Mechanical Engineering

University of MarylandCollege Park, MD 20742-3035


Introduction To minimize environmental effects of HVAC systems,

their direct and indirect GHG emissions should be reduced.

Use working fluids with ultra-low GWPs Improve the efficiency of vapor compression cycles Develop a new cooling technology, which uses

working fluids with ultra-low GWPs and is more efficient.

This work presents the overview of caloric cooling technologies.

4


Introduction

3

Not-in-kind Cooling Technologies

Solid-State

Magnetocaloric

Electrocaloric

Elastocaloric

Thermoelectric

Thermoionic

Heat activated

Absorption

Adsorption

Ejector

Vuilleumier heat pump

Gaseous

Thermoacoustic

Brayton heat pump

Stirling heat pump

Vortex-tube

Pulse-tube

Liquid-vapor

Membrane heat pump

Metal hydride

Electro-chemical

compression

Others

Malone cycle


Caloric Cooling Process

4

Kitanovski et al., IJR, 57 (2015)

Brayton Cycle


Active Caloric Regeneration Process

5



Magnetocaloric (MC)

6


MC Working Principle

7

Refrigerant is solid, and the system requires a heat transfer fluid to exchange

heat with the conditioned space.

Refrigerant is fluid and moves through the conditioned space to

exchange heat.


List of Magnetocaloric Cooling Projects

8



Magnetic Material: La(Fe-Mn-Si)13

9

L. Huang, D. Y. Cong, L. Ma, Z. H. Nie et al., Large reversible magnetocaloric effect in a Ni-Co-Mn-Inmagnetic shape memory alloy, Appl. Physics Letters, 108 032405 (2016).


Magnetic Material: La(Fe-Mn-Si)13

10

M. Krautz, K. Skokov, T. Gottschall, C.S. Teixeira, A. Waske, J. Liu, L. Schultz, O. Gutfleisch,Systematic investigation of Mn substituted La(Fe,Si)13 alloys and their hydrides for room-temperature magnetocaloric application, AIP. 118, 053907 (2015).


ELICit: EUs Research Project

11

European Union (EU) started the three year researchproject, ELICiT Environmentally Low Impact CoolingTechnology in 2014 to enhance the commercialization ofmagnetic cooling.

The ELICiT Project focused on applying magnetic coolingto domestic refrigeration.

Objectives are: Life Cycle Optimization System Optimization Benchmarked Validation Regulations and Standards


ELICit: Camfridge

12

Magnetic cooling can double COP than R600a freezer Pump efficiency doubled. Optimized HXs Volume of three magnetic cooling systems:

Camfridge: 5,292 cm3 Astronautics: 86,400 cm3 CoolTech: 784,000 cm3

Used shaped magnetic material/HXs (others use sphere orpowder) to make a compact system

Source: ICR 2015, Yokohama, Japan


ELICit: CoolTech

13

2 heat exchangers and 2 small pumps to circulate HTF For 380 liter volume cabinet, achieved 3.5-4.2C Tcabin at 21.5C

Tamb, Power 38 W with direct HX loop Designed for wine cooler: capacity 200 W, COP 4.54, Achieved

-4C Tlow and 40C Thigh at 20C Tini

http://www.cooltech-applications.com/magnetic-refrigeration-system.html


MC Challenges

14

Magnetocaloric effect decreases as temperature moves away from Curie temperature, thus efficiency of all cycles degrades with increasing temperature lift.

Need multi-stage cycles using different Curie temperatures as each stage can make only 1-2 K.

Pumping power is a larger contributor to loss than in vapor compression; systems require 25~60X more pumping power.


Electrocaloric (ETC)

15


List of Electrocaloric and ElastocaloricCooling Projects

16



Electrocaloric: Polymer

17

Zhang et al, 2015. Adv. Materials.


Electrocaloric: Ceramic

18

Zhao et al, 2015. J. Alloys & Compounds. 653 (2015).

Developed PLZST 2/57/38/5 anti-ferroelectrics (AFE) thick films with ZrO2 buffer layer on LNO bottom electrodes

Achieved an enhanced relative dielectric constant and a reduced leakage current. Improved ECE by about 10 K from 27.3C to 37.1C at room temperature 21C.

The corresponding entropy changes are 31 and 42 J/kg-K.


Electrocaloric: Ceramic

19

S. Hirasawa, T. Kawanami, K. Shirai,, American J. of Physics and Applications, 4 (2016) 134-139.

Predicted average heat flux performancewas 70 kW/m2 with 1,000 Hz frequencyand the 20 m thicknesses of theelectrocaloric material and 20 m heatstorage material.


ETC Challenges

20

The limitation in the shape of the materials. Only thin films can be applied since a high electric field is needed (hundreds of MV/m).

Lacking of ETC multilayer modules with high reliability (> 100 cycles) and high ETC performance (DT > 5 K),

There is no ETC device demonstration reported showing large temp. span (> 10 K) with any cooling power.

Source: Q. M. Zhang, Penn State, 2016


Elastocaloric (ESC)

21


Elastocaloric Effect

22

LiquidPsat < Psys

VaporPsat < Psys

Martensitesat < sys

Austenitesat < sys

Apply stress (compression) /pressure to the system

C C

Pressure induced

condensation

C C

Austenitesat > sys

Martensitesat > sys

Remove stress/pressure to the system

LiquidPsat > Psys

VaporPsat > Psys

C C

Pressure induced boiling

CC


Elastocaloric Cooling

23

https://www.nature.com/articles/nenergy2016159/figures/1


Comparison of Elastocaloric Materials

24


(isothermal)

Can we increase latent heat, reduce heat capacity, lower operational stress, and increase work recovery?

Comparison of Elastocaloric Materials

25


Elastocaloric Effect in Ni-Ti Wire

26

3 mm Nitinol (Ni-Ti alloy) 3 mm NiTi wire Tad ~ 17K Martensite

Austenite phase change (solid)

Direction for material developments

High latent heat (Ni-Ti 12 J/g) Low transitional stress (Ni-Ti

700 MPa) Long fatigue life (Ni-Ti >

360,000 cycles) Low hysteresis to reduce

loss (Ni-Ti 1 J/g)

Cui et al., 2012, App. Phy. Lett., 101, 073904

ad = 24K

ad = -17K


Elastocaloric Effect in Ni-Ti Ribbon

27

Ni-Ti (50.8/49.2)DTad ~ 9.5 K

M. Schmidt, A. Schutze, S. Seelecke, Int. J. Refrig. 54 (2015) 88-97.


Elastocaloric Effect in NiTiFe Film

28

Ossmer et al., Smart Mater. Struct. 25 (2016) 085037.

NiTiFe (49.1/50.5/0.4) 3 micron foil DTad ~ 9.4 K


ESC Prototype: NiTi Tube

29

Nitinol tube holder

Water in Water out

Compressible solid: Deformation: 0.5 (12.7 mm), which is 5% of 10 (254

mm) tube Force: each tube requires 1,350 lbf (6 kN)

Nitinol tubes

Linear bearing

Hexagon arranged NiTi (SMA) tubes in

each bed

OD = 4.72 mmID = 3.76 mm


ESC Prototype: Ni-Ti Tube

30

Work recovery: two beds were 50-50 percent pre-compressed

Linear actuator attached to the moving box

Ni-Ti bed

Loading Head & Water Distributor

Linear actuator

Top view


ESC From Material to System

31

Entropy

T

1

3

4

100%M

0%MMartensite

2

Austenite56

Th

Tc

Entropy

1

3

4

100%M

0%M

2

Austenite56

T

MartensiteTh

Tc

Entropy

1

3

4

100%M0%M

2

Austenite56

T

MartensiteTh

Tc

Loading/unloading Heat transfer Heat recovery

Same initial temperature

T4 < T1!

V1 V2

V3 V4

V5 V6

V7 V8

HRV

Pump 1 Pump 2

Pump 3

Bed #1

Bed #2

TcTh

V1 V2

V3 V4

V5 V6

V7 V8

HRV

Pump1 Pump2

Pump3

Bed #1

Bed #2

TcTh

V1 V2

V3 V4

V5 V6

V7 V8

HRV

Pump 1Pump 2

Pump 3

Bed #1

Bed #2

TcTh


ESC-NiTi Tube: Temperature Lift

32

Without compression: all fluid temperatures are following the same trend

With compression: temperature lift exists

V1 V2

V3 V4

V5 V6

V7 V8

Pump1

Pump2

Bed #1

Bed #2

Heat rejection loop(To ambient)

Cooling delivery loop(To target space)

Heat recovery loop(Internal)

T6T5

T7T8

Heat sink

Mass flow meter 1

Mass flow meter 2

Electric heater

MFM

MFM

T2

T1 T3

T4

Pump3

HRV2

HRV1

20

20.5

21

21.5

22

22.5

23

1 11 21 31 41 51

Tem

pera

ture

[C

]

Time [min]

TC5-cooling inlet CTC6-cooling outlet CTC7-heating inlet CTC8-heating outlet C

Measured fluid temperature variations

T6

T5T7

T8

22

23

24

25

26

27

28

29

30

0 10 20 30 40

Tem

pera

ture

[C

]

Time [min]

TC5-cooling inlet CTC6-cooling outlet CTC7-heating inlet CTC8-heating outlet C

Temperature lift72F

80F

76F

84F


ESC-NiTi Tube: Performance Progress

33

Adding screw jack + rail V layout Vertical alignment

Adding 0.002 shims

Horizontal alignment of

linear actuator

Horizontal alignment

2x locking nuts

Screw jacks

Friction problem: 7 tubes up to 3.8% strain

Sep, 2014May, 2014

Tlif

t[K

]

Jan, 2015 Jul, 2015

1.3 K

1.8 K

Plastic tubes distributor

Fluid

Fluid

Nitinol tubes

Rubber seal

Plastic tubesLoading head (dry)Holder

Original design (fluid contacts metal loading head directly)Challenge 1: leak through distributor Challenge 2: leak

through rubber

To PEEK tubes on the other side

Challenge 3: PEEK tubes inside loading head

Heat loss from water to the metal loading heads

2.8 K

10 tubes, 3.4% strain

7 tubes, 4% strain 10 tubes,

4% strain

4.2 K

Limitation of two motors

13

42

4.7 K

Dead thermal mass of HTF


ESC-NiTi Tube: Test Results

34

Maximum cooling capacity: 65 10 W Maximum temperature lift: 4.7 0.4 K

4.8 K

Achieved 4.7 K Tlift when using plastic insertions to block 50% HTF inside tubes

Measured 9% heat loss from Ni-Ti tubes to the holder

Adding 12 W parasitic heat generated from pumps + 9% heat loss 6.1 K Tlift6.1 K

PEEK means plastic insulation tubes to reduce heat loss to the metal loading heads


ESC Challenges

35

Material development Large latent heat, low transitional stress, low

hysteresis and long fatigue life Custom shape/structure manufacturing capability

Cycle design: high frequency heat transfer feature

System integration Compact and light system High efficient heat transfer High efficient heat recovery/regeneration Cost down


Performance Comparison

36

Technology mat @ Tlift = 10 K sys @ Tlift = 10 K sys,max @ Tlift

Vapor compression 0.88 0.20 0.27 @ 24 K

Magnetocaloric 0.91 0.29 0.30 @ 9 K

Electrocaloric 0.41 n/a n/a

Elastocaloric 0.63 0.14 0.16 @ 17 K


Summary of Cooling Technologies

37

Technology R&D statusCost/

complexity RefrigerantWork

input form

Possible heat recovery method

Possible work

recovery method

Vapor compression (baseline)

Mature Low R410A pdv Suction-line heat exchanger Expander

Magnetocaloric Advanced R&D High Gd 0HdmActive

magnetic regenerator

Multi-bed rotary bed

design

ElectrocaloricR&D,

recently started

Moderate P(VDF-TrFE-CFE) EdDPassive external

regeneratorn/a

Elastocaloric R&D,

recently started

Moderate Ni-Ti d Thermowaveheat recovery

Multi-bed symmetric

design


Solid-state caloric cooling technologies are advancing among NIKs because of new material development.

Summarized the working principles and recent advancements of caloric cooling technologies.

Solid-state caloric technologies are applicable to small temperature lift applications if single stage is used and require more development in both materials and system integration.

Conclusions

38


Thanks for your attention!

Any Questions?

39

Slide Number 1IntroductionIntroductionCaloric Cooling ProcessActive Caloric Regeneration ProcessMagnetocaloric (MC)MC Working PrincipleList of Magnetocaloric Cooling ProjectsMagnetic Material: La(Fe-Mn-Si)13Magnetic Material: La(Fe-Mn-Si)13ELICit: EUs Research ProjectELICit: CamfridgeELICit: CoolTechMC ChallengesElectrocaloric (ETC)List of Electrocaloric and Elastocaloric Cooling ProjectsElectrocaloric: PolymerElectrocaloric: CeramicElectrocaloric: CeramicETC ChallengesElastocaloric (ESC)Elastocaloric EffectElastocaloric CoolingComparison of Elastocaloric Materials Comparison of Elastocaloric MaterialsElastocaloric Effect in Ni-Ti WireElastocaloric Effect in Ni-Ti RibbonElastocaloric Effect in NiTiFe FilmESC Prototype: NiTi TubeESC Prototype: Ni-Ti TubeESC From Material to SystemESC-NiTi Tube: Temperature LiftESC-NiTi Tube: Performance ProgressESC-NiTi Tube: Test ResultsESC ChallengesPerformance ComparisonSummary of Cooling TechnologiesConclusionsThanks for your attention!Any Questions?

Documents

Advances in Caloric Cooling Technologiesiccr.xjtucompressor.com/file/ppt/5ICCR2017 Keynote--Hwang.pdfThe 8th International Conference on Compressors and Refrigeration, Xi’an, China,